update dependencies (#2241)

- acorn@5.1.1
- commander@2.11.0
- mocha@3.4.2

package.json

@@ -29,12 +29,12 @@
     "LICENSE"
   ],
   "dependencies": {
-    "commander": "~2.9.0",
+    "commander": "~2.11.0",
     "source-map": "~0.5.1"
   },
   "devDependencies": {
-    "acorn": "~5.0.3",
-    "mocha": "~2.3.4",
+    "acorn": "~5.1.1",
+    "mocha": "~3.4.2",
     "semver": "~5.3.0"
   },
   "scripts": {